In the traditional Public Switched Telephone Network (PSTN), network elements are typically equipped with order wire (OW) electronics for supporting voice communications between such network elements. For example, referring to FIG. 1, there is shown a portion of the PSTN 10 comprising a plurality of network elements 12 interconnected by an electrical OW 14. Each network element 12 maintains OW interface electronics 16 for supporting voice communications with other network elements 12 over the electrical OW 14.
The above-described OW system is typically used by PSTN installation and maintenance personnel. For example, PSTN maintenance personnel may use the above-described OW system to communicate between network elements within a same network site or at different network sites for localizing and repairing failures in the PSTN, or during coordinated maintenance activities such as, for example, provisioning and testing of new services.
Since the traditional PSTN is an electrical-based system, it is relatively straightforward to implement the above-described electrical-based OW system therein. It is also relatively straightforward to implement an OW system in a next generation synchronous optical network (SONET), despite the fact that a SONET system is a combined optical- and electrical-based system. That is, each network element in a SONET network supports optical-to-electrical (O/E) and electrical-to-optical (E/O) conversion functions. Thus, voice communications may be carried between network elements via an OW system in a SONET network using these O/E and E/O conversion functions. In fact, the benefits of an OW system in a SONET network are so great that the standards governing SONET networks mandate the use of an OW system. Specifically, the SONET standards requirements for such an OW system in a SONET network are to embed a narrow band channel (64 kilobits per second (kbps)) in a SONET overhead for carrying voice communications between network elements. These requirements were drafted to insure support for legacy systems, which only contemplated voice communications for the OW system. Indeed, because of its relatively slow transmission rate, the narrow band channel defined in the SONET standards only permits voice communications. However, to more efficiently perform installation and maintenance activities at network sites, it would be desirable to transmit data and video communications in addition to voice communications.
In a latest generation photonics network, there are no O/E and E/O conversion functions in network elements. An optical signal is generated from a first node outside the photonics network and, after passing through the photonics network, the optical signal is terminated at a second node outside the photonics network. Network elements in the photonics network optically route the optical signal through the photonics network without any O/E or E/O conversions. As there is no electrical connectivity between network elements, there is also no means of supporting voice communications. Thus, installation and maintenance personnel performing installation and maintenance activities at network sites in a photonics network must rely on cell phones and/or the traditional PSTN for voice communications in order to coordinate their tasks.
In view of the foregoing, it would be desirable to provide a technique for providing inter-nodal communications in a photonics network to overcome the above-described inadequacies and shortcomings. Indeed, as telecommunications technology has evolved into the photonic domain, there is a need to provide inter-nodal communications capabilities in this photonic domain. Furthermore, as discussed above, to more efficiently perform installation and maintenance activities at network sites, it would also be desirable to introduce new functions in photonics network elements so as to enable them to support data and video communications in addition to voice communications.